Optical brighteners derived from 3, 5-diaminopyrazine-2, 6-dicarboxylic acid



United States Patent i e 3,369,018

Patented Feb. 13, 1968 Y represents a divalent aliphatic radicalcontaining at 3,369,018 least two carbon atoms, and preferably not moreOPTICAL BRIGHTENERS DERIVED FROM than 12 carbon atoms, and more inparticular alkyl- A gl g DICARBOXYLI'C ene, alkylene-O-alkylene,alkylene-NH-alkylene, al- Gaudenz Girell Di Giovanoel, Munchenstein,Basel-Land, kenylime especlany zlnylene or cycloalkylene ReinhardZweidler, Basel, and Rodolphe Vonderwahl, ,especlally CyclohexyleneReinach, Basel-Land, Switzerland, assignors to J. R. R and R eachrepresent alkyl! Preferably of 1 to 4 Geigy A.G., Basel, Switzerlandcarbon atoms, or cycloalkyl especially cyclohexyl or No Drawing. FiledOct. 20, 1964, Ser. No. 405,231 aralkyl, preferably benzyl or phenethyl;or Claims priority, application Switzerland, Oct. 29, 1963, 10 R and Rtogether with the nitrogen to which they 13,225/63 are linkedalternatively form a heterocyclic ring; 7 Clalms- (Cl-260 250) and Zrepresents hydrogen or inert substituents as defined further below, toform a compound of the ABSTRACT OF THE DISCLOSURE formula N Compounds ofthe formula B R N L CHaNH-C0r l CO-NH 1; J CHQNH N mat-0H3 z J AXY-N l Ij AXYW 3" CH3 NH \N NH CH3 Z (In) wherein wherein A, X, Y, R, R", and Zhave the same A i ith SO or CO meanings as in Formula II, and preferredoptical X i i h NH or 1 1 1 but can brighteners according to theinvention are obtained also be owhen A is co y Y is a divalent aliphaticradical containing from 2 to 12 (b) Qufitermzmg a compound of Formula HIcarbon atoms, an alkylatlng or aralkylating agent to form a compound Zis either hydrogen or an inert substituent, and of the formula N\ G9orn-nrvomf l- NH B R, 6

An CH3NH JNHCH3 z A-X-Y-N R" W is either a tertiary or quaternary aniongro wherein R represents an alkyl radical, preferably of from 1 to 4carbon atoms, which may be optionally subkare optical bnghtemrs foracrylomtnle polymer fiber mastituted, or an aralkyl radical, A11represents an anion,

tenals' and A, X, Y, R, R, and Z have the same meanings as 40 inFormulaII, supra. The present invention concerns new optical brighteners It IsSurpnsmg that may the gioup which are derivatives of3,5-diaminopyrazine-2,6-dicarboxylic acid, processes for the productionthereof, a process for the optical brightening of polymeric or coupolymeric acrylonitrile fibers as well as, as industrial products, theacrylonitrile polymer fiber materials in the Compound Formula 111 15qllateffllzed 1n Vlew optically brightened therewith. of the fact thatthis compound has a total of at least five It has been found that newoptical brighteners which baslc centers In Its molecule' are derivativesof 3,S-diaminopyrazine-2,6-dicarboxylic In a prefered group of optlcalbnghteners accrdmg i can be produced by to the mventlon, Y represents analkylene radical of the (a) Reacting a compound of the formula formula swherein n is an integer from 2 to 6 or the 1,2- or 1,4-

' cyclohexylene radical.

In this preferred group of optical brighteners X rep- \N/\ resents NH-,R represents alkyl of from 1 to 4 car- CHKNH NHCHs (I) bon atoms,cyclohexyl, benzyl or phenethyl, and R" repwith an amine of the formularesents alkyl of from 1 to 4 carbon atoms.

When R and R together with the nitrogen to which HzN B they are linkedform a heterocyclic ring, this is, prefer- J ably in a saturated-membered cycle, especially the piper- Z J AXYN idine or morpholinering.

(H) Most preferred are optical brighteners according to the invention inwhich each of R and R"'represents a Wherem lower alkyl radical,especially methyl or ethyl.

A represents 40 or CO, preferably SO Optional substituents Z of ring Bare, in particular, low- X represents N(R)-, or, in the case of A beinger alkyl groups, e.g. the methyl or ethyl group, or lower CO, X can alsobe O., R representing hydroalkoxy groups such as the methoxy or ethoxygroup, or

gen or a lower alkyl group, but X preferably halogen, e.g. fluorine,chlorine or bromine. However, in

representing NH--, the preferred group of optical brighteners accordingto 3 the invention, Z represents hydrogen, i.e. ring B is not furthersubstituted.

In the preferred group of brighteners R is the methyl or ethyl radicalor the benzyl radical. In the most preferred brighteners according tothe invention R represents the benzyl radical.

Starting materials of Formula I have been described in Belgian PatentNo. 568,115.

Starting materials corresponding to Formula II are obtained, forexample, by reacting a nitrobenzene-Iior -4- sulfonic acid or carboxylicacid chloride with a compound of the formula wherein X, Y, R and R" havethe meanings given in Formula II and then reducing the nitro group tothe amino group.

The reaction of the pyrazine carboxylic acid chloride of Formula I withthe amine of Formula II to form the compound of Formula III is performedadvantageously in an inert organic solvent, preferably in a liquidorganic tertiary nitrogen base such as pyridine, optionally in thepresence of an inert organic diluent, e.g. an unsubstituted orsubstituted hydrocarbon such as toluene or chlorobenzene,dichlorobenzene, ornitrobenzene.

The tertiary amino group in compounds of Formula III is quaternized toform ammonium compounds of Formula IV by the action of an alkylating oraralkylating agent. This reaction is preferably performed in an inertorganic solvent of the type mentioned above, advantag'eously at a raisedtemperature. Suitable alkylating or aralkylating agents are the estersof low alkanols or aralkanols with strong inorganic or organic acids.Examples of such esters are: alkyl or aralkyl halides such as methyl-,ethyl-, propyl-, butylor benzylchloride, bromide or -iodide, ordialkylsulfates such as dimethyl or diethyl sulfate, or anyl sulfonicacid alkyl esters, e.g. ptoluene sulfonic acid methyl or ethyl ester,also low esters, amides and nitriles of halogenalkane or halogenalkenecarboxylic acids. Benzylchloride is preferred.

A modification of the process according to the invention consists inreacting a compound of the formula CHaNH C Hr- NHxN Starting materialsotFormula VI are obtained by condensing a compound of Formula I with a3- or 4-aminobenzene sulfonic or carboxylic acid and converting theacylamino acid obtained into the corresponding acid chloride, forexample with thionyl chloride or a phosphoric acid chloride.

The reaction of the acid chloride of Formula VI with the compound ofFormula IV is performed under the conditions described in the firstprocess.

The new compounds of Formulas III and IV are pale yellowish to yellowishpowders. In contrast to the previously known brighteners of the pyrazineseries which draw on polyamide fibers but not on acrylon-itrile fibersin spite of the fact that they possess basic centers in their molecules,it is surprising that the new compounds draw from aqueous baths ontopolymeric or copolymeric acrylonitrile fibers and impart a brilliantwhite aspect to these fibers.

The com-pounds according to the invention are used for the brighteningof these materials in liquors, which may be acid, and which contain thebrightener in amounts of 0.01 to 0.2%, calculated on the fibers; acidscontained in these liquors are, erg. acetic acid, oxalic acid or formicacid. The liquors may also contain other additives such as non-ionogenicWash-active substances, e.g. fatty alcohol polyglycol ethers.

It is also possible to impregnate the brighteners mentioned from thefoulard and to develop them by a hot, moist treatment, preferably bysteaming. If desired, the foulard baths can contain any surface activedispersing agents desired as well as organic acids. But similarly goodwhite effects are also obtained without acid.

The new brighteners can also be incorporated in neutral or weaklyalkaline Washing liquors containing the anionic or, preferably,non-ionogenic washing agents usual in laundering.

It is also possible to incorporate the new brighteners into polymeric orcopolymeric acrylonitrile spinning masses.

The following examples illustrate the invention. The temperatures aregiven therein in degrees centigrade.

Example 1 (a) 25.7 g. of 3,5-bis-rnethylamino-pyrazine-2-carboxylic acidmethylamide-6-carboxylic acid chloride, produced by treating thecorresponding carboxylic acid with thionyl chloride, are suspended in500 ml. of chlorobenzene and the suspension is slowly added dropwise,while stirring well, to a solution of 25.7 g. of1-aminobenzene-3-sulfonic acid-'y-(dimethyl-amino)-propyl-amide in 300ml. ofpure pyridine and 200 ml. of chlorobenzene. The reactiontempenature is kept at 5. The reaction mixture is then stirred for 12 to16 hours at 0, then the temperature is raised to 50 and kept there for ashort time, after which the pyridine and chlorobenzene are removed bysteam distillation. The dark brown residue, while still hot, isneutralized with about 20 g. of sodium carbonate whereupon furtherpyridine is removed by steam distillation. The reaction mixture is thencooled and the precipitate is filtered ofif under suction.

A dark brown, resinous substance is obtained. This is dried in vacuo andthen recrystallized from a mixture of 500 ml. of chlorobenzene and500ml. of ligroin. Yellow crystals separate out which correspond to thetert. amino compound (M.P. 161-163", uncorrected) of the (formula Thistert. amino compound is suitable for the brightening of polymeric andcopolymeric acrylonitrile by the exhaustion process.

(b) 47.8 g. of tertiary amino compound are dissolved in 300 ml. ofanhydrous chlorobenzene. 13.8 g. of benzyl' 6 is dried in vacuo andrecrystallized from isobutanol. The A dark brown solution is obtained asresidue. This is neucompound obtained has the formula tralized withsodium carbonate and again subjected to N ea OHa-NH-CO- o ONH l I ICHaNH NHCH; SOzNHCH2CHzOHa-N-OH&

It is a microcrystalline, white to pale yellow powder steam distillationto remove the remaining pyridine. The which melts at 193-195(uncorrected). This compound reaction mixture is then cooled and theprecipitate formed draws from an acid to neutral bath onto polymeric oris filtered off under suction. copolymeric acrylonitrile fibers andgives this material The dark brown amorphous mass is dried in vacuo anda pleasant bluish white appearance. then recrystallized from ethylacetate. Pale yellow crys- The 1-aminobenzene-3 -sulfonic acid'y-(dimethylamitals are obtained of the formula no)-propyl-amide used inthis example is obtained by which melt at 214-216 (uncorrected). Thiscompound reacting l-nitrobenzene-S-sulfonic acid chloride with'y-didraws well from an acid liquor onto polymeric andcomethylamino-propylamine and reducing the nitro group polymericacrylonitrile fibers and has a good brightening to the amino group.power.

Compounds having a similar brightening effect .on (b) This tertiaryamino compound is quaternized by polymeric or copolymeric acrylonitrilefibers are obtained the method described in paragraph 3 of Example 1 ex:if, in the above example, instead of the 25.7 g. of l-aminocept that,instead of 13.8 g. of benzyl chloride, the equibenzene 3 sulfonic acid'y-(dimethyl-amino) propylmolar amount of dimethyl sulfate is used asquaternizing amide, the equimolar amount of 1-aminobenzene-4-sulagent.In this'way, the compound of the formula N EB CH;NHCO CO-NH CH I ISolon; CHaNH NlNHCHa C ONHCHa-CHa-CHr-NCH3 CHa fOHiC a v-( m hv min )prwlm de, m n is obtained. It is a microcrystalline yellow powder whichbenzene-3- or 4-sulfonic acid B-(dimethyl-amino)-ethylmelts at 208-210(uncorrected) and it has good afiinity amide, 1-aminobenzene-3- or4-sulfonic acid B-(diethylto and good brightening power on acrylonitrilepolymers. amino)-ethyl-amide, l-aminobenzene-Iior 4-sulfonic acid The1-aminobenzene 3 carboxylic acid 'y-(dimethyl--(dimethyl-amino)-hexyl-amide, 1-aminobenzene-3- or amino)-propyl-amideused in the above example is ob- 4-sulfonic acid g-(diethyl-amino)-hexy1amide, or l-amitained by reacting 3-nitrobenzene-l-carboxylic acid ch10-no-4- or 6-methylbenzene-3-sulfonic acid 'y-(dimethylride with'y-(dimethyl-amino)-propyl-amine and then reamino)-propyl-amide, or1-amino-4- or 6-methylbenzener ducing the nitro group to the aminogroup. 3-sulfonic acid y-(dimethyl-amino) -a1lyl-amide or 1- Tertiaryamino compounds having a brightening power amino-4- or6-methylbenzene-3-sulfonic acid 'y-(dirnethylon polymeric andcopolymeric acrylonitrile similar to the amin0)-cyC10heXY1-amide 0r6-methyl entertiary amino compounds obtained according toparazene-3-sulfonic acid v-(dimethyl-amino)-lauryl-amide, is graph 1 ofthis example, are obtained if, in the above instead of the 0f beI1ZY1Chloride, the example, instead of the 22.1 of1-aminobenzene-3-carequimolar amount of dimethyl or dlethyl sulfate,p-toluboxylic acid 'y-(dimethyl-amino)-propyl-amide, the equienesulfonic acid methyl or ethyl ester, or methyl bromide olar amou t ofthe ta tin at rial given in Column or ethyl bromide methyl iodide orethyl iodide is used II of the following Table I is used and otherwisethemeand otherwise the procedure given in the ex ple is cedure given inExample 2, paragraphs 1 and 2 is 01- folloWedlowed. Column III shows theuncorrected melting points Examplez of these tertiary amino compounds,namely, under (a) (a) 25] of 3,5 bis methy1amin0 pyrazine z carbox thoseof the crude and (b) those of the purified products. ylicacid-methylamide-G-carboxylic acid chloride are sns- If ternary o flompunds so obtained are repended in 500 ml. of chlorobenzene. Thesuspension is acted W1 th quatermzmg glven 111 column slowly added,while stirring well, to a solution of 22.1 descnbed m Paragraph 3 ofthls example then l of l aminobanzene 3 carboxylic acid 7,(d-Lmethy1 amithe same procedure, compounds are obtained having the n0) pmpy1 amide in400 of ethanol and 0 1 melting points given in Column V. These compoundshave of pure pyridine. The reaction temperature is 50-60". Similarbrightening POWer 011 Polymeric p y The reaction mixture is then stirredfor 16 hours at 60, acrylonitrile t0 the Product Obtained according Pafter which the solvent is removed by steam distillation. graph 3 ofthis example.

amide.

boxylic acid fl(iethyl mino)-ethylamide:

l'aminobenzened-carboxylic acid -y-(di et-hyl-aminc)-propylamide:

r boxylic acid 'y-(diethy1-a1nino)-propylamide:

(b i-arninobenzene-B-carboxylic acid -(dimethyl-amino)- propyl-amide.l-amino-3-chlorobenzene-'i-carboxylie acid -(dimethylamino)-propyl-arnide. l-amino-El-methylbenzenei-cerboxylic acid'y-(dimethyl-aminmpropyharnide. i-amino-benzerie-carboxylic acidB-(diethyl-amino)-ethyl ester (produced as described in Example 13below).

1 214216 Benzyl chloride.

91-92" Diethyl 230233 sulfate.

Example 13 25.7 g. of 3,S-bis-methylamino-pyrazine-2-carboxylicacid-methylamide-6-carboxylic acid chloride are suspended in 500 ml. ofchlorobenzene. The suspension is slowly added, while stirring well, to asolution of 23.6 g. of 1- aminobenzene-4-carboxylic acid,6-(diethyl-amin0)-ethyl ester in 150 ml. of pure pyridine. The reactiontemperature is kept at 50-60 and the mixture is. then stirred for 16hours at 60. Steam is introduced into the reaction mixture to remove thepyridine and chlorobenzene. The dark brown solution obtained isneutralized with sodium carbonate, further pyridine is removed by steamdistillation, the reaction mixture is then cooled and the precipitateformed is finally filtered off under suction.

The reaction product is a dark brown substance. It is purified bydissolving it in acetone and filtering it through an aluminum oxidecolumn. After evaporation of the 501- vent, the purified product isrecrystallized from acetone/ pentane (volume ratio 1: 1). Pale yellowcrystals are obtained which are of the formula and have a melting pointof 7476 for the crude and 91-92 for the purified product.

This substance draws onto polymeric or copolymeric acrylonitrile fibersfrom a hot acid bath and lends a bluish white appearance to thesesubstrate.

The l-aminobenzene 4 carboxylic acid [3 (diethylamino)-ethyl-ester usedin this example is obtained by reacting 1-nitrobenzene-4-carboxylic acidchloride with ,8- diethylamino-ethyl alcohol.

If in the above example, instead of 23.6 g. ofl-aminobenzene-4-carboxylic acid p-(diethyl-amino)-ethyl ester, theequivalent amount of one of the starting materials given in Column II ofthe following Table 2 is used and otherwise the procedure given in theexample is followed, then the corresponding end products falling underFormula III are obtained. These products have a brightening effect onpolymeric or, copolymeric acrylonitrile fibers.

TABLE 2 I II Starting materials 14 1-aminobenzene-fi carboxyiic acidfi-(diethylamino)-ethyl ester. 1-arniriobenzene-3-carboxylic acidB-(dibenzylamino)- ethyl ester.

16 l-aminobenzene-4-carboxylic acid B-(dibcnzylamino)- ethyl ester.

17 l-aminobenzene-Ii-carboxylic acid fl-(dicthylamino-fiethoxy)ethylester.

18 l-aminobenzenei-carboxyllc acid B-(diethylamino-B- ethoxyl-ethylester.

19 l-arninobenzene-B-carboxylic acid B-(dimethylamino-B- ethylimino)ethyl ester.

7 Example 20 41.2 g. of the acid chloride of the formula N C-HaNHCO-CO-NH- NHCHa SOr-Cl are suspended in 500 ml. of chlorobenzene and asolution of 10.2 g. of 'y-dimethylaminopropylamine in ml. of purepyridine is added. The mixture is heated to 5060 and stirred for 16hours at this temperature. The solvent is removed from the reactionmixture by steam distillation, the brownish solution so obtained isneutralized with sodium carbonate and the remaining pyridine is removedby steam distillation.

A substance is obtained which is identical with the tertiary aminocompound obtained according to step (b) of Example 1.

It is quaternized as described in the example.

The acid chloride used as starting material is obtained by reacting 3,5bis methylamino-pyrazine-Z-carboxylic acid methylamide-6-carboxylic acidchloride with 1- amino-benzene-3-sulfonic acid and converting theresulting acid to its chloride.

Example 21 37.6 g. of the acid chloride of the formula N CHz-NIiE-COTYeoman-Q CHs-NH NHCH; C0-C1 A dark-brown substance is obtained which ispurified in the same manner as described in Example 2 and which isidentical with the tertiary amino compound obtained Example 22 100 g. ofpolyacrylonitrile yarn (Orlon 42 of Du Pont de Nemours, Wilmington,Del., USA.) are introduced into 3000 ml. of water containing 0.1 g. ofthe compound of the formula given in paragraph 3 of Example 1, 4 g. of85% formic acid and 2 g. of the condensation product of ml. of ethyleneoxide and 1 mol of octadecyl alcohol. The bath is heated to 50 and then,within 30 minutes, to the -boil and kept at the boil for another 30minutes. The yarn is then taken from the bath, rinsed with cold waterand dried.

A strong brilliant white effect on this yarn is obtained by thistreatment.

The same result can also be obtained with the other compounds mentionedin Examples 2 to 21 instead of with the compound according to Example 1.

Example 23 Orlon staple fiber fabric is impregnated in the foulard witha solution containing 2 g. of the brightener given in paragraph 2 ofExample 1 in 1000 ml. of warm Water and is then steamed, withoutintermediate drying, for 15 minutes at 100-102. A very strong whiteeffect is attained on this fabric in spite of the fact that the liquorcontains no acid. The white effect attained after the goods have beensteamed is not influenced by the addition of 4 ml. of formic acid per1000 ml. impregnating liquor.

On adding a mixture of 1 part of bis-(B-hydroxyethyD- amine salt ofcoconut oil fatty acid and 1 part of coconut oil fattyacid-N,N-bis-(B-hydroxyethyl)-amide to the foulard bath, a visible whiteeffect is obtained without steaming, which white effect is strengthenedby subsequent steaming.

Example 24 Example 25 g. of bleached triacetate charmeuse (Tricel ofI.C.I. London, England) are washed for 45 minutes at 90 in 1000 ml. ofwater containing 1 g. of the condensation product of 1 mol of nonylphenol and 11 mols of ethylene oxide, 2 g. of sodium tripolyphosphate, 2g. of sodium sulfate and 0.03 g. of the brightener given in Example 1,paragraph 2. The goods are rinsed cold and dried.

A very strong brightening effect is attained on the triacetate materialin this way.

N CHaNH-CO:[ Imam-Q N 1 0 Example 26 40 g. of Orlon staple fiber fabricare washed for 45 minutes at in 1000 g. of water containing 2 g. of thecondensation product of 1 mol of octyl phenol and 10 mols of ethyleneoxide, 3 g. of sodium sulfate and 0.05 g. of the brightener given inparagraph 3 of Example 1. The goods are rinsed cold and dried.

The Orlon material is greatly brightened in this way.

Example 27 25.7 g. of3,5-bis-methylamino-pyrazine-Z-(N-methylcarbamyl)-6-carboxylic acidchloride are suspended in 500 ml. of chlorobenzene and are slowly addeddropwise while stirring well to a solution of 27.1 g. ofl-aminobenzene-3-sulfonic acid N-methyl N-fi-(methylethylamino)-ethylamide in 300 ml. of pure pyridine and 200 ml. of chlorobenzene. Bycontinuing in accordance with Example 1, the optical brightener of theformula is obtained which draws well on polyacrylonitrile fiber.

The 1 amino benzene-3-sulfonic acid-N-methyl-N-fi-(methylethyl-amino)-ethyl amide used in this example is obtained byreacting 1-nitrobenzene-3-sulfonic acid chloride withN-methyl-N'-methylethyl-ethylene diamine and reducing the nitro group tothe amino group.

A compound with similar optical brightening effect on polymer andcopolymer acrylonitrile fibers is obtained when in Example 27, insteadof the 27.1 g. of l-aminobenzene 3 sulfonic acidN-methyl-N-fi-(methylethylamino)-ethyl amide, the equimolecular amountof lamino-benzene-3-sulfonic acid-N ethyl N B (methylethyl-amino)-ethylamide is used and otherwise the procedure according to Example 27 isfollowed.

We claim:

1. An optical brightener capable of drawing on polyacrylonitrile fibermaterials and of the formula A is a member selected from the groupconsisting of SO and -CO;

X is N(R) when A is SO and X is a member selected from the groupconsisting of -N(R)- and O, when A is CO-, R being a member selectedfrom the group consisting of hydrogen and lower alkyl;

Y is a divalent aliphatic radical containing at least two and not morethan 12 carbon atoms;

each of R and R" is, independently, a member selected from the groupconsisting of alkyl of 1 to 4 carbon atoms, cyclohexyl, benzyl andphenethyl; and

R and R taken together with the nitrogen to which they are linkedalternatively are a member selected from the group consisting ofpiperidino and morpholino; and

Z is a member selected from the group consisting of hydrogen and inertsubstituents free from interfering with the optical brightening effectand the drawing power of said brightener on said fiber material.

2. An optical brightener capable of drawing on polyacrylonitrile fibermaterials and of the formula 3,369,018 1 1 12 wherein R and R" takentogether with the nitrogen to which A is a member selected from thegroup consisting of they are linked altefnttwely a member Selected andfrom the group consisting of pipendlno and morpho- XsNRwh A S-adX ammhersele cte d from i he g r oup ilsistiii of N(R Z 18 a member siflectedtha group conslistlng of and When A is R a member hydrogen and inertsubstltuents free from interferselected frdrn the group consisting ofhydrogen and {Hg Wlth the Optical tinghtenmg and the a lower lalkyl. mgpower of said brightener on said fiber material;

\ n! I, Y is a divalent aliphatic radical containing at least twoerepresenti ahyl f m i and not more than 12 Carbon atoms; m n represen san anion ree rom 1n er ering Wit e each of R and R is, independently, amember selected Rtica1 brightening effect and the.drawing Power of fromthe group consisting of alkyl of 1 to 4 carbon 3 2 g? sald i atoms,cyclohexyl, benzyl and phenethyl; and noptlca ng enero t e 0mm 3 4. Anoptical brightener of the formula 5. An optical brightener of theformula CHa {B 6. An optical brightener of the formula CH2 CHz-NH NH-CHa1 9 7. An optical brightener of the formula CzHu NICHOLAS S. RIZZO,Primary Examiner.

